Most pesto sauces have a secret ingredient that makes them a major no-no for folks who don’t eat animal products. So, what’s the non-vegan culprit? It’s cheese. Parmesan cheese is a popular addition to the top of any pasta, but most of us don’t expect it to be mixed into the sauce. It is, however, a staple ingredient in most pesto sauces (via La Cucina Italiana).
You may be wondering why this cheesy secret ingredient can’t just be removed for folks who steer clear of dairy products. While most of us probably don’t think we notice the Parmigiano-Reggiano or Pecorino cheese that’s added to pesto sauce, it’s actually part of what makes pesto what it is (via Healthline). Cheese adds to pesto’s unique flavor. Additionally, in an otherwise uncooked sauce, cheese melts when it touches hot pasta to make the dish warm and rich. As surprising as it may be to discover that pesto isn’t vegan, removing the ingredient in question is likely to totally change this beloved sauce.